The invention relates generally to remote ultrasonic measurements and, more particularly, to a wireless transceiver for remote ultrasonic measurements.
Ultrasonic probes are used to perform a variety of measurements including measuring the distance from a target. An exemplary conventional ultrasonic pulser/receiver 10 is illustrated in FIG. 1, in block form. A pulse generator 1 supplies a large amplitude, radio-frequency (RF) tone burst, typically on the order of 10–100 kHz upon receiving a start measurement request signal. The pulse can be amplified, as needed, by an amplifier 2. A transducer 3 is excited by the tone burst, emitting a sound wave that is reflected from a target (not shown). The transducer, emits an electronic echo signal in response to the reflected wave. The electronic echo signal can be amplified by an amplifier 4 and converted to a digital representation by converting circuitry 5 for processing by a computer (not shown).
In one application of interest, ultrasonic probes are used to measure material levels within storage silos, e.g. grain level. Briefly, the ultrasonic probe ascertains material level by measuring the echo time of flight of an ultrasonic pulse and the ambient temperature. The distance between the probe and the grain level can then be calculated using the echo time and the ambient temperature. The ultrasonic transceiver of FIG. 1 is conventionally employed for these ultrasonic level measurements.
A typical ultrasonic level sensing system 20 is illustrated in FIG. 2, in block form. The level sensing system includes a number of ultrasonic transducers 3 and a central processing unit (CPU) 6. The transducers are situated in separate silos and are connected to the CPU by cables 7. Because of the size of the silos, the cables are long, with lengths of up to 100 feet or more. The use of the long cables undesirably increases the time and labor costs of installation of the ultrasonic level sensing system. Accordingly, it would be desirable to eliminate the cables.
One possible solution would be to control each transducer individually, so as to eliminate the need for the CPU. However, given that the transducers are relatively inexpensive and processing units are quite expensive, such a solution would dramatically increase the cost of the ultrasonic level sensing system. Further, both simultaneous control of the transducers and central collection of the level measurements are desirable. Accordingly, the proposed solution would not alleviate the need for connections to a CPU.
Accordingly, it would be desirable to develop a wireless ultrasonic measurement system that provides wireless connections between a number of transducers and a remote control unit. In addition, it would be desirable to provide wireless connections between the transducers and a central data processor. Further, it would be desirable for the wireless connections to operate at frequencies in the Industrial, Scientific and Medical (ISM) band.